Do the QR codes look blurred or anything when you print them out? The only other thing I can think of is that your camera might not be getting enough light – when you read a code off a screen the code itself is emitting light but with a physical code your 3DS might be blocking the light and making it too dark to read.

The QR codes are blurred and I doubt it’s because it’s not getting enough light because I noticed that when playing the AR games so I knew to check for lighting problems. I guess it’ll only work if I print it out as a whole page >.<

I might have worked it out – unless you click on the link to get to the image you just see the thumbnail, which is blurred. I’ve added a note to the posts and changed the size of the thumbnail, so hopefully that should make everything clearer.